Hi Glenn,
there is always something better and more costly..
The simple code reader is based on blinks (counts returned from the Control unit).
In my opinion, this is the most cost effective reader for Models equipped with OBD (
On
Board
Diagnostic) before 1996.
I didn't see anything that would hint on what model you want to use the reader with?
For vehicle equipped with OBD II e.g. 1996 and after, it would probably be more informative to purchase a device that was designed to work with OBD II equipped vehicle.
For OBD til 1995 (maybe even later), there is a system used by Mercedes Dealerships, I believe it is called "Star System" but the cost is far and beyond.
Also, there are some Software based diagnostic systems available. They, mostly involve a computer and some ISO interface (for example:
Diagnostic Code Reader Tool Mercedes w 124 201 300E 320 190E E320 300TE OBD1 | eBay) that may or may not be easy to understand.
Bottom line, the count reader, is easy to built (so I say, ha) maybe a little more inconvenient to use and requires your attention, while pulling the code(s), but will give you in conjunction with the appropriate
code table, just enough information to be dangerous, ha.
I wouldn't bother to look for something better, because better in this department means more money.